JPH04275046A - Vibration motor for pager - Google Patents

Abstract

PURPOSE:To prevent the start failure due to contact inferiority between a brush and a commutator and add vibration force, in the vibration motor being stored for the call of a vibration type pager a mobile telephone. CONSTITUTION:A soft magnetic material or a permanent magnet is attached to one part of a rotor, over a pair of poles of a field so as to increase whirling force, and also the stoppage position is regulated by the said soft magnetic material or the permanent magnet so that the said rotor may not stop at the position where a brush sits astride between commutators.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating motor for use in vibrating pagers or mobile telephones (hereinafter referred to as pagers).

0002

2. Description of the Related Art A pager is desired to have a small external size and a thin shape, has a large vibration force, does not generate noise, consumes little current, and is inexpensive. A vibration motor that satisfies these market demands is a micro commutator motor with a cylindrical or disc-shaped coreless rotor, which is composed of a thin rare-earth permanent magnet as a narrow cylindrical or ultra-thin field. It is used. However, micro commutator motors may not be able to start due to poor contact between the brushes and commutator pieces at low voltages. The pager's power source is usually a single cell battery at 1.3V, and the inability to start the motor is a serious defect that leads to failure of the paging signal, so reliable startup must be guaranteed under all environmental conditions.

FIG. 4(a) is a half-sectional view of a conventional vibration motor composed of a cylindrical coreless rotor. It is composed of a coreless rotor 3 and a thin rare earth permanent magnet field 4 facing the rotor winding. The coreless rotor 3 is connected to the shaft 5 via a commutator 6. The motor is driven by supplying current from the commutator 6 to the windings of the rotor 3 via the brushes 7.

FIG. 4(b) shows the storage structure and vibration mode of the vibration motor in the pager case. The drive motor 2 is located inside the case 8, and in order to reduce the thickness B of the case, motor. As the drive motor 2 rotates, the counterweight 1 swings around from the rotation center P as shown in the figure. The whirling moment is determined by the product of the distance L between the center of gravity of the counterweight 1 and the center of rotation P and the centrifugal force of the counterweight 1, and the centrifugal force is determined by the square of the rotational speed of the motor, the center of gravity force, and the center of gravity of the counterweight. It is clear that it depends on the product of the radii of motion. The vibrations occur in all directions including the two surfaces A and B of the case 8.

FIG. 5(a) shows a cross section of a conventional vibration motor composed of a flat coreless rotor.In the motor body 9, the winding coil of a disc-shaped coreless rotor 10 is used. The thin plate-shaped rare earth permanent magnet field 11 faces the shaft 12, and the plate-shaped coreless rotor 10 faces the shaft 12.
is connected to via a commutator 13. The motor is brush 1
A current is supplied from the commutator 13 to the windings of the rotor 10 via the commutator 13. However, the difference from the cylindrical shape is that instead of a counterweight, the plate rotor 10 has an eccentric center of gravity with respect to the axis.

Regarding the effect of this eccentric center of gravity, FIG. 5(b) shows the vibration mode of the flat vibration motor. The vibration motor 9 is attached to the pager case 1 as shown in FIG. 5(b-2).
It is stored in 5. The vibration mode is vibration on the motor shaft as shown in FIG. 5(b-1), and the cause of this is the plate rotor 10.
This is the axial force component due to the variation in the symmetric forward torque distribution direction. Symmetrical forward torque distribution means that the component force in the axial thrust direction, which is generated as a result of the torque distribution of the couple due to the winding coils distributed symmetrically around the shaft, is generated by the fluctuation of the couple torque (wow). This is the variation in the thrust direction.

The vibration component on the B side of the case 15 as shown in FIG. No. 10 causes rotational rotation with respect to the axis. Fig. 5 (b-3) shows the eccentric center of gravity of the disc-shaped rotor 10 caused by the same situation as Fig. 5 (b-2) in which the coils of the rotor 10 are arranged asymmetrically, and the weight effect for the eccentric center of gravity is intentionally added. This is the whirling of the shaft on one side that occurs when In the case of a pager, the vibration modes shown in Figures 5 (b-2) and (b-3) are effective; Figure 5 (b-2) shows the vibration of the B side of the case 15, and Figure 5 (b-3) shows the same vibration mode. This becomes the runout component of the A side.

In particular, the vibration mode shown in FIG. 5(b-2) is related to the vibration center P, and the vibration moment is related to the distance L from the axial component of the eccentric torque to the operation center. It is desirable that the moment force is large. Figure 5
The vibration mode (b-1) is suppressed by the rigid body of the motor case and is not useful for extracting vibration output. As described above, the role of the eccentric center of gravity that contributes to vibration is different between a cylindrical vibration motor that swings around with a counterweight and a flat motor that has an eccentric rotor. Especially in flat motors, the asymmetric torque distribution has a large effect on vibration force.

[0009]

[Problems to be Solved by the Invention] As mentioned above, pagers generally use low-voltage, low-cost micro commutator motors powered by single-cell batteries, but they cannot be started due to poor contact between the brush and commutator. There is always a fear associated with it. The present invention aims at alleviating this drawback and at the same time adding vibrational force.

0010

[Means for Solving the Problems] The inventors' research focuses on commutator material, structure, and dimensional accuracy, and brush material and structure. We use a variety of methods such as spring pressure, but low voltages such as 0.7
The inability to start at around V is the most severe in the spark generation state. In other words, it has been found that the motor is frequently stopped at a position where the brush straddles the commutator pieces.

The present invention provides a commutator-type coreless motor that extracts whirling vibration force by giving an eccentric center of gravity to the armature rotor, in which a soft magnetic material or a permanent magnet is attached to a part of the rotor across one pole pair of the field. This is a vibration motor for a pager that increases whirling force and at the same time regulates the stop position using a soft magnetic material or a permanent magnet so that the rotor does not stop at the position where the brush straddles the commutator pieces.

[0012] In a motor having a cylindrical structure, the counterweight is made of a magnetic material, and at least one of the counterweights is permanently attached to the outer periphery of the counterweight, which must be attracted so that the brush stops at a position where it does not cross between the commutator pieces of the motor. A member made of a magnet is disposed, and a soft magnetic body is disposed at a symmetrical position opposite to one pole or axis of a rotating electric machine and a fixed field having a cylindrical structure. In addition, in a motor configured with a flat plate armature rotor, a member made of a soft magnetic material is arranged for one pole of the stator field facing in the plate armature winding, and its position is When stopped, the brush is attracted to a position where it does not straddle the commutator pieces and stops, and one or more brushes are installed in the disc-shaped armature winding at an asymmetric position with respect to the axis, facing the poles of the stator field. A plurality of permanent magnet poles of the same polarity are arranged.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1(a) shows an example of a cylindrical motor according to the present invention, the structure of which is based on FIG. 4. The counterweight 1 is made of a soft magnetic material and is connected to the motor 2 by a shaft. It consists of a permanent magnet 16 placed around a counterweight, and a yoke 17 bonded to the opposite surface of the permanent magnet 16 to the counterweight 1. For example, if the permanent magnet has two poles for the eccentric counter yoke 1 as shown in the figure, there will be four cogging points, two attraction points when stopped, and the rotor will always stop at the center of the permanent magnet's pole (counter (ignoring the effects of weight eccentricity).

When fixing the counter to the shaft, the relative position of the brush and commutator can be determined based on the magnitude of the current flowing into the rotor, so the counterweight 1 can be fixed to the shaft in a position where the brush does not straddle between the commutator pieces. can. Also, the generated cogging torque appears as speed fluctuations of the rotating counterweight. Since the centrifugal force is the product of the eccentric center of gravity and the square of the speed, this speed fluctuation is also reinforced as a vibration element. Fig. 2(a) shows the torque fluctuation ω at a point where the commutator piece is 3 segments and the suction stop point of the bipolar permanent magnet 16 of the counterweight 1 is 30° from the point where it straddles between the brush and the commutator piece.
, where the solid line is the variation due to commutator segment switching, the dotted line is the variation due to the counterweight, and the two-dot chain line is the composite torque variation. In addition, if the rotational speed variation due to this torque variation is expressed as a projection f from a certain stationary point as a vibration due to whirling due to the eccentric center of gravity, it can be expressed as a projection f from a certain stationary point.
). The resultant vibration looks like a chain double-dashed line in figure (b). As a result, vibration change degree and amplitude are co-reinforced.

FIG. 1(b) shows another embodiment of a cylindrical motor, in which a soft iron plate 18 is added to the motor of FIG.
is attached to the side surface of the support portion of the commutator 6 via the shaft 5. In this figure, the soft iron plate 18 has a two-pole configuration. FIG. 3(a) is a diagram illustrating the relative position of each part in FIG. 1(b). That is, the numbers of each part indicate the same parts as in FIGS. 4 and 1. The stopping point is at the point where the brush 7 is shifted by 30 degrees from the gap between the pieces of the commutator 6, and the pole center of the soft iron plate 18 and the permanent magnet field 4
The pole centers of the two coincide with each other, and the relationship between the winding coils of the rotor 3 at that time is shown. In this way, the cogging torque due to the pole plates with symmetrical poles has twice the number of poles as in the case of the counterweight shown in Fig. 2, so it is twice as large as the number of poles, and is shown in Fig. 2 (b).
) to the vibration component also increases. However, the soft iron plate is not involved in the eccentric center of gravity.

FIG. 3(b) shows a flat coreless vibration motor (
FIG. 5) shows an example of three rotor coils and three commutator segments to which the present invention is applied, and the symbols are the same as those in FIG. 5. The parts added as part of the present invention are such that a soft iron pole or a permanent magnet field pole of the same polarity is placed at the center of two coils of the two windings of the rotor 10 to face the permanent magnet field pole 11. -2) In addition to increasing the B-plane runout of the case 15, when the permanent magnet field 11 and the permanent magnet 19 of the same polarity are attracted to each other at the same time, the brush 14 is prevented from straddling between the pieces of the commutator 13. I made it.

In FIG. 3(c), the three plate-shaped rotor coils in FIG. 3(b) are in a Y-connection, but in a V-connection, and although electrically symmetrical, the positional coil arrangement is different. This figure shows an example in which an eccentric center of gravity is added to the disc-shaped rotor 11 to make it asymmetric. Although the present invention has been described with reference to two poles of the permanent magnet field, it goes without saying that even in the case of multiple poles, the present invention is applicable to the positional arrangement of the rotor coils in the same electrical relationship that opposes them.

[0018]

[Effects of the Invention] According to the present invention, in a vibration motor for a pager, it is possible to start the motor with high reliability, and at the same time, it is possible to apply a large vibration force.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram and an end view of an embodiment of a cylindrical motor according to the invention as seen in the direction of the arrow.

FIG. 2 (a) is a torque variation diagram according to the present invention in a commutator 3 segment bipolar permanent magnet field, and (b) is a diagram of the stationary point projection according to the present invention in a commutator 3 segment bipolar permanent magnet field. Schematic diagram of vibration.

3(a) is an explanatory diagram of the relative position of each component of FIG. 2 according to the present invention, (b) is an explanatory diagram of the relative position of each component of the flat motor according to the present invention, and (c) is an explanatory diagram of the relative position of each component of the flat motor according to the present invention. FIG. 4 is a diagram illustrating the relative positions of other components of the flat motor according to the above.

[Fig. 4] (a) is a partial cross-sectional view of a vibration motor configured with a cylindrical coreless rotor, and (b) is an explanation of the vibration mode inside the pager case of the vibration motor configured with a cylindrical coreless rotor. figure.

FIG. 5(a) is a sectional view of a flat coreless vibration motor according to the present invention, and FIG. 5(b) is an explanatory diagram of vibration modes in the pager case of the flat coreless vibration motor.

[Explanation of symbols]

1 Counterweight 2 Cylindrical motor body 3 Coreless rotor 4 Permanent magnet field 5 Shaft 6 Commutator 7 Brush 8 Pager case 9 Flat motor body 10 Coreless rotor 11 Permanent magnet field 12 Shaft 13 Commutator 14 Brush 15 Pager case 16 Permanent magnet 17 York 18 Soft iron plate 19 Permanent magnet

Claims (5)

[Claims] Claim 1: In a commutator-type coreless motor that extracts whirling vibration force by giving an eccentric center of gravity to the armature rotor, a soft magnetic material or a permanent magnet is attached to a part of the rotor across one pole pair of the field, and the brushes are A vibration motor for a pager, characterized in that a stopping position of the rotor is regulated by the soft magnetic material or a permanent magnet so that the rotor does not stop at a position straddling between commutator pieces. 2. A counterweight of a motor having a cylindrical structure is made of a magnetic material, and the outer circumference of the counterweight is to be attracted so that the brush stops at a position where it does not straddle between the commutator pieces of the motor.
Claim 1, further comprising a member at least one of which is made of a permanent magnet.
Vibration motor for pager. [Claim 3] A pager according to Claim 1, comprising a motor having a cylindrical structure and a member made of a soft magnetic material arranged at one part facing one pole of the fixed field or at a symmetrical position opposite to the motor with respect to the shaft. vibration motor. 4. A motor configured with a flat plate-shaped armature rotor, in which one soft magnetic material is arranged for one pole of the stator field facing in the disc-shaped armature winding; 2. A vibrating motor for a pager according to claim 1, wherein the brush is sucked and stopped at a position where the brush does not straddle the commutator piece when stopped. 5. In a motor constituted by a flat plate-shaped armature rotor, in a disc-shaped armature winding, one is located at an asymmetric position with respect to the axis, facing the pole of the stator field.
2. The vibration motor for a pager according to claim 1, further comprising one or more permanent magnet poles of the same polarity.